The Jugular-fishes.—In all the families of spiny-rayed fishes, as ranged in order in the present work, from the Berycidæ to the Soleidæ, the ventrals are thoracic in position, the pelvis, if present, being joined to the shoulder-girdle behind the symphysis of the clavicles so that the ventral fin falls below or behind the pectoral fin. To this arrangement the families of Bembradidæ and Pinguipedidæ offer perhaps the only exceptions.

In all the families which precede the Berycidæ in the linear series adopted in this work, the ventral fins when present are abdominal, the pelvis lying behind the clavicles and free from them as in the sharks, the reptiles, and all higher vertebrates.

In all the families remaining for discussion, the ventrals are brought still farther forward to a point distinctly before the pectorals. This position is called jugular (Lat. jugulum, throat).

The fishes with jugular ventrals we here divide into six groups, orders, and suborders: Jugulares, Haplodoci, Xenopterygii, Anacanthini, Opisthomi, and Pediculati. The last two groups, and perhaps the Anacanthini also, may well be considered as distinct orders, being more aberrant than the others.

For the most primitive and at the same time most obscurely defined of these groups we may retain the term applied by Linnæus to all of them, the name Jugulares. This group includes those jugular-fishes in which the position of the gills, the structure of the skull, and the form of the tail are essentially as in ordinary fishes. It is an extremely diversified and perhaps unnatural group, some of its members resembling Opisthognathidæ and Malacanthidæ, others suggesting the mailed-cheek fishes, and still others more degenerate. The fishes having the fins thus placed were long ago set apart by Linnæus, under the name of "Jugulares," Callionymus being the genus first placed by him in this group. Besides their anterior insertion, the ventrals in the Jugulares are more or less reduced in size, the rays being usually but not always less than I, 5 in number and more often reduced to one or two, or even wholly lost.

In general, the jugular fishes are degenerate as compared with the perch-like forms, but in certain regards they are often highly specialized. The groups showing this character are probably related one to another, but in some cases this fact is not clearly shown. In most of the jugular-fishes the shoulder-girdle shows some change or distortion. The usual foramen in the hypercoracoid is often wanting or relegated to the interspace between the coracoids, and the arrangement of the actinosts often deviates from that seen in the perciform fishes.

The Weevers: Trachinidæ.—Of the various families the group of weevers, Trachinidæ, most approaches the type of ordinary fishes. In the words of Dr. Gill, these fishes are known by "an elongated body attenuated backward from the head, compressed, oblong head, with the snout very short, a deeply cleft, oblique mouth, and a long spine projecting backward from each operculum and strengthened by extension on the surface of the operculum, as a keel. The dorsal fins are distinct, the first composed of strong, pungent spines radiating from a short base and about six or seven in number. The second dorsal and anal are very long. The pectorals have the lower rays unbranched, and the ventrals are in advance of the pectorals, and have each a spine and five rays. The species of this family are mostly found along the European and western African coast; but singularly enough a species closely related to the Old World form is found on the coast of Chile. None have been obtained from the intermediate regions or from the American coast. Two species are found in England, and are known under the name of the greater weever (Trachinus draco), about twelve inches long, and the lesser weever (Trachinus vipera), about six inches long. They are perhaps the most dreaded of the smaller English fishes. The formidable opercular spines are weapons of defense, and when seized by the fisherman the fish is apt to throw its head in the direction of the hand and lance a spine into it. The pungent dorsal spines are also defensive. Although without a poison gland, such as some fishes distantly related have at the base of the spines, they cause very severe wounds, and death may occur from tetanus. They are therefore divested of both opercular and dorsal spines before being exposed for sale. The various popular names which the weevers enjoy, in addition to their general designation, mostly refer to the armature of the spines, or are the result of the armature; such are adder-fish, stingfish, and sting-bull."

No species of Trachinidæ is known from North America or from Asia. In these fishes, as Dr. Boulenger has lately shown, the hypercoracoid is without foramen, the usual perforation lying between this bone and the hypercoracoid. A similar condition exists in the Anacanthini, or codfishes, but it seems to have been developed independently in the two groups. In the relatives of the Trachinidæ the position of this foramen changes gradually, moving by degrees from its usual place to the lower margin of the hypercoracoid. Species referred to Trachinus are recorded from the Miocene as well as Trachinus.

The extinct group of Callipterygidæ found in the Eocene of Monte Bolca seems allied to the Trachinidæ. It has the dorsal fin continuous, the spines small, the soft rays high; the scales are very small or wanting. Callipteryx speciosus and C. recticandus are the known species.

The Nototheniidæ.—In the family of Nototheniidæ the foramen is also wanting or confluent with the suture between the coracoids. To this family belong many species of the Antarctic region. These are elongate fishes with ctenoid scales and a general resemblance to small Hexagrammidæ. In most of the genera there is more than one lateral line. These species are the antipodes of the Cottidæ and Hexagrammidæ; although lacking the bony stay of the latter, they show several analogical resemblances and have very similar habits.

The Harpagiferidæ, naked, with the opercle armed with spines, and resemble sculpins even more closely than do the Nototheniidæ. Harpagifer is found in Antarctic seas, and the three species of Draconetta in the deeper waters of the North Atlantic and Pacific. These little fishes resemble Callionymus, but the opercle, instead of the preopercle, bears spines. The Bovichthyidæ of New Zealand are also sculpin-like and perhaps belong to the same family. Dr. Boulenger places all these Antarctic forms with the foramen outside the hypercoracoid in one family, Nototheniidæ. Several deep-sea fishes of this type have been lately described by Dr. Louis Dollo and others from the Patagonian region. One of these forms, Macrias amissus, lately named by Gill and Townsend, is five feet long, perhaps the largest deep-sea fish known. The family of Percophidæ, from Chile, is also closely allied to these forms, the single species differing in slight respects of osteology.

Closely related to the family of Nototheniidæ and perhaps scarcely distinct from it is the small family of Pteropsaridæ, which differs in having but one lateral line and the foramen just above the lower edge of the hypercoracoid. The numerous species inhabit the middle Pacific, and are prettily colored fishes, looking like gobies. Pteropsaron is a Japanese genus, with high dorsal and anal fins; Parapercis is more widely diffused. Osurus schauinslandi is one of the neatest of the small fishes of Hawaii. Several species of Parapercis and Neopercis occur in Japan and numerous others in the waters of Polynesia. Pseudeleginus majori of the Italian Miocene must belong near Parapercis.

The Bathymasteridæ, or ronquils, are perhaps allied to the Nototheniidæ; they resemble the Opisthognathidæ, but the jaws are shorter and they have a large number of vertebræ as befits their northern distribution. Ronquilus jordani is found in Puget Sound and Bathymaster signatus in Alaska. The ventral rays are I, 5, and the many-rayed dorsal has a few slender spines in front.

The Leptoscopidæ.—The Leptoscopidæ of New Zealand resemble the weevers and star-gazers, but the head is unarmed, covered by thin skin.

The Star-gazers: Uranoscopidæ.—The Uranoscopidæ, or star-gazers, have the head cuboid, mostly bony above, the mouth almost vertical, the lips usually fringed, and the eyes on the flat upper surface of the head. The spinous dorsal is short and may be wanting. The hypercoracoid has a foramen, and the body is naked or covered with small scales. The appearance is eccentric, like that of some of the Scorpænidæ, but the anatomy differs in several ways from that of the mailed-cheek fishes.

The species inhabit warm seas, and the larger ones are food-fishes of some importance. One species, Uranoscopus scaber, abounds in the Mediterranean. Uranoscopus japonicus and other species are found in Japan. Astroscopus y-græcum is the commonest species on our Atlantic coast. The bare spaces on the top of the head in this species yield vigorous electric shocks. Another American species is Astroscopus guttatus. In Japan and the East Indies the forms are more numerous and varied. Ichthyscopus lebeck, with a single dorsal, is a fantastic inhabitant of the seas of Japan, and Anema monopterygium in New Zealand.

Uranoscopus peruzzii, an extinct star-gazer, has been described from the Pliocene of Tuscany.

The Dragonets: Callionymidæ.—Remotely allied to the Uranoscopidæ is the interesting family of dragonets, or Callionymidæ. These are small scaleless fishes with flat heads, the preopercle armed with a strong spine, the body bearing a general resemblance to the smaller and smoother Cottidæ. The gill-openings are very small, the ventral fins wide apart. The colors are highly variegated, the fins are high, often filamentous, and the sexes differ much in coloration and in the development of the fins. The species are especially numerous on the shores of Japan, where Callionymus valenciennesi, Callionymus beniteguri, and Calliurichthys japonicus are food-fishes of some slight importance. Others are found in the East Indies, and several large and handsome forms are taken in the Mediterranean. Callionymus draco, the dragonet, or "sculpin," reaches the coast of England. In America but three species have been taken. These are dredged in deep water in the East Indies. In other parts of the world these fantastic little creatures are shore-fishes, creeping about in the shallow bays. Species of Synchiropus, colored like the coral sands, abound in the Polynesian coral reefs.

A fossil species of Callionymus (C. macrocephalus) are found in the Miocene of Croatia.

The family of Rhyacichthyidæ is a small group of Asiatic fishes allied to the Callionymidæ, but less elongate and differing in minor details. They are found not in the sea, but in mountain streams. Rhyacichthys (formerly called by the preoccupied name Platyptera) is the principal genus.

The Trichonontidæ, with wide gill-openings and cycloid scales, are also related to the Callionymidæ. The species are few, small, and confined to the Indian and Australian seas. Another small family closely related to this is the group of Hemerocœtidæ of the same region.

The Dactyloscopidæ.—In this and the preceding families of jugular fishes the ventral rays remain I, 5, as in the typical thoracic forms. In most of the families yet to be described the number is I, 3, a character which separates the little fishes of the family of Dactyloscopidæ from the Uranoscopidæ and Leptoscopidæ. Dactyloscopus tridigitatus is a small fish of the coral sands of Cuba. The other species of this family are found mostly in the West Indies and on the west coast of Mexico. Several genera, Myxodagnus, Gillellus, Dactylagnus, etc., are recognized. In the structure of the shoulder-girdle these species diverge from the star-gazers, approaching the blennies, and their position is intermediate between Trachinidæ and Blenniidæ.